Power-hammer and means of operating same.



BATENTEDJAN, 8', 1907;.

H. B,- ST 0GK$ POWER HAMMER AND MB-A'Nspr OPERATINGISAME APPLICATION rlLnfimAmz, 1906.

3' SHEETS-SHEET 1.

R I PATEfiTBD-JAH. a, 10074 S QGKS- APPLICATION TILED MAR. 26, 1 906.

POWER HAMMER AND MEANS-0P OPERA-TING SAME.

Wmm

No. 840,668. 'PATENTED JAN. 8,-1907 v 11. B. sTocKs. v 'POWBR HAMMER AND MEANS OF OPERATING SAME.

- APPLICATION FILED MAB..26,1906.

3 SHEETS-$31531 3..

.ARRY BENWELL sTocKs.

of Lancaster,

cation filed by me on August 31,1905.

specification.

THE. cLIMAx PATENTS 1a. sauces.

Toall whom'it indjljconcerns 7 Be, it known-that I, HARRY BENWELL STocKs, engineer, a subject. of the Kin' of" Great Britain, residin at 107 Barlow oor road, Didsbury, Manc ester, in the county Operating Same, of which the following is a My invention relates to ower-hammers and similar percussive too s actuated by pneumatic pressure and to means for operatlng the.same ,such as described in an applia rial No. 276,0(10, of which this application is a division.-

With each 'powe'r hainmer I useza separate air-compressor and two air-conducting tubes, and as a novel feature of I vide means whereby the pressure obtained'at each impulse of the compressor is withheld e tubes" from thetool until a p'redetermined pressure is attained within thetubes conductingjthe- .ower to the tool. On

within t the pressure within t above the spring-10a ed valves is overcomeiby such excess ressure and conducts'the air to one side or ot er of the reci rocat'ingiston-h'ammer within the tool. e'pistonlat'nrnerof the 'e tubes being raised tool is unaffected unless and until the 5 re-' quired. predeterminedjpressure is exceeded, when the spring-loaded valves in the tool-are overcome, as explained, and, the ressure is 3 utilized with a sudden'ilnpulse an at its full intensity at each. end of the piston-hammer alternately to actuate the piston-hammer.

I. thus obtain the most effective stroke'with out any loss of energy and at great economy in theconsumption of power. I also arrange that afargreater ressure shall'be delivered behind thepistonammerion its outward or workingstroke than .on the return or Idle stroke, as will be explained in the course of thufollowing description.

In order that my invention may be fully understood, I will now proceed to describe it in detail with the aid of the accompanying drawings, to which I will refer.-

Fi 'ure 1 ofthe drawings illustrates, on a small scale, a sectional side elevation of the I I Specification. ofl etters Patent. A leseedfiled-Marches, 1906. Serial 110.308.083-

England, have invented a new or' Improved Power-Hammer and- Means of my invention I pro redetermined degree, system of suction-valve i, which is-drawn o PATENT oFFIon.

DEMANCHESTER, ENGLAND,- ASSIGNOR' TO LIMITED, OF MANCHESTER, ENGLAND.

"P WE' B-HAMME AND- MEANS or OPERATING S ME.

"Patented Jan. 8, 1907.

Fig; 8is a detail view. Fig. 9 shows a side elevation of the compressor and an end view of the tool, the air-compressor and the tool being connected together by the air-tubes. In the first place I will describe in detail the construction of the air-compressor, al-' I not 0 aim such a compressor to be novel er se. Such compressor consists of cylin ers a (tin line, in which'work trunk-pistons b b. All the arts of the compressor at the left hand of willlbe understood that the internal parts at the right hand, which are shown in the drawthough' I wish ity to be understood that I do ig. 1 are shown in section, and it ings in outside view, are. similar and need ndt.

be illustrated. 1

. The trunk-pistons b b are -connected together b a rectangular frame 1;, in which slides a 'e-blo'ck (1, connected to a crank e,

which is common'to both pistons. On thef crank-shaft f is mounted a pulley g, by means of which theshaft is revolved by a belt fron anyasuitable source of power, an'dthe shaft 8 5- also carries a fly-wheel, Aswill be understood, the rotation of the crank-shaft effects the reciprocation of the trunk-pistons .b b. In.

-conjunction with suclipiston b I rovide a its: seat against the action of aspring" on the forward movement of. the piston,- admitting air to the I cylinder. on the'return stroke of the piston the suction-valve if is closed, the air iscom:

pressed, and finally forces a delivery or nonreturn valve k ofi' its seat a ainst the action of a spring m, the air being d elive ed through the orifice n. Each of the delivery-orifices 1:. n in practice is connected by flexible tubing" n n to the power-hammer and arranged to conduct the corn ressed air, one tube leading to the rear of. t e piston-hammer and the other to the front thereof, in manner to be hereinafter explained. The heat generated "by the compressed'air may be dissipated by jacketed with inlet and outlet p,.(or 'vice 3 as a portable hand-tool.

' give a high initialvelooity and power to the piston-hammer, while the valve 3may be versa,) the Water-jackets of the two cylinders being connected together at g and r by means-of a suitable pipe 1" 4 The power-hammer may be of any suitable size andis shown on Sheet 2=of the drawings The cylinder 8 (which may be formed in one or more parts,

' as may be convenient when constructing the tool) is bored out for the reciprocating pis mg by the non-return valves is in the comton-hammer t, which on its forward. stroke actuates a suitable chisel or tool inserted in the bush u, as usual. At the rear end of the tool is inserted a bush or cylinder 1), closed at 'each end by plugs w and containing a double piston-valve w w, connected together'by a stempc A port 1 is formed inthe cylinders, leading to the front of the piston-hammer t, and a short port z'leads to the rear of the piston-hammer. On air being admitted to the tool the double piston-valve is arranged to govern these ports to inlet and exhaust. The

.air-i'nlet: 2 t0 the port y is governed by a spring-loaded valve 3, a spring-loaded valve 4 governing the air-inlet 5 to the port 2, the

' valves being arranged, by preference, as close as possible to the ports 3 2. The spring-loaded valves are differentially loaded, .the valve 4, which admits the pressure for the forward or workin stroke of the piston-hammer t, being loade to admit air only at a high pressure say, for instance, eighty poundsto loaded to admit air at a greatly-reduced pressure-saytwenty pounds'sufiicient to return the piston-hammer promptly to its initial starting-point for the next stroke; thus econ-. omizing power.

of example only and maybe varied. The flexible tubes n conducting air under pressure to the piston-hammer,- are connect-ed at .6 6. t. The air-ports 2 and 5 also communicate by passages? 7- to .an exhaust or outlet 8, formed in the handle 8 of the tool and governed by a spring-valve 9 actuated by a piv- The cylinder 1) is formed with apertures 11, leadin to a."chamber 12, in which are bored vho es 13, communicating with the atmosphere. The cylinder 8 is provided with "a hole or holes 14, which serve as exhaustports for the airat the end of each forward and backwardstroke of the hammer.

Having thus indicated in detail the construction of the compressor and the powerhammer, the'niethod of working and operation will be readily gathered from thefolloW- ing description.

It I will be understood, of' course, that the'sepressures are given by way The air under pressure is delivered through two flexible tubes n to the tool in alternate impulses on every stroke of the compressor, as described. When the tool is not at work,

the valve 9 is in the position shown .in-Fig. 4

and the air under pressure escapes readily to atmosphere out of the exhaust-aperture 8, so that there is no necessity to stop the compressor when the working of the tool'is temporarily suspended. To start work, the lever 10 is depressed by the workman to close the exhaust 8 by means of the valve 9, and

this position of the valve 9 is maintained while the tool is at "WOIk. The air is now confined within the flexible conducting-tubpressor and the spring-loaded valves 3 and 4. inthe hammer. Assume the parts to be in the position shown in Fig. 4 and the piston hammer t is at the end of its forward stroke. As soon as the predetermined pressurein the conducting-tube n, leading to the valve 3, is exceeded suflicient' to force this valve off its seat the"air is admitted via the port. 2 and the port y to the front of the piston-hammer t, which is forced backward, expelling the air behind it through the short port z throu h the apertures 11 in the cylinder '1) into t ie the chamber 12, and to atmosphere through the holes 13, as clearly indicated by the arrows in Fig. 4. return the pistonhammer and which may, as explained, he of comparatively low pressure is practically exhausted inefi'ectmg this work, and the front exhaust-port 14 is un coveredin advance of the piston-hammer t, allowing any air above atmo'sphericressurc to escape. On the reverse stroke of t 1e compressor if the pressure-attained thereby in, the flexible tube n, .l'e ding to the spring-loaded valve 4, exceeds the predetermined limit this valve is in turn forced off its seat, the air insinuating itself behind. the iston valve :r (the pistons being formed witli cross-grooves r to facilitate this) and traversin it, together withthe attached piston-Va vc' x in The impulse thus required to thecylinder v, to open the port 2 to air under .viding for a high initial and sustained ve ocity of working stroke or blow, while air in front of the piston-hammer is exhausted via the port y through the apertures'in the cylinder r to the chamber 12, and so to atmosphere, as already described. 4

It will be understood that on first closing the valve 9 a number of strokes of the compressor may be needed to bring the ressure 1n the tubes n to the predetermine degree.

The number of such strokes will depend ontirely on the length and diameter of'the flexiv a by throttling til the predetermined pressure is exceeded, vwhich strong springs'would 'be difficult tovalve-spindle in the chamber 10 will assist that when thevalve'ls opened the spring will "more readily collapse to the pressure and per- 7 hit the valve torem'ain open until the pressure again falls to the normal.

i 4 is such 'as' will maintain suflicient pressure of 'qilil'ed velocity, when the predetermined pressure-has been once a'ttained. Thereforebegin stroke inefie'ctively 'as soon as the generation of air-pressure is-commenced by 1 penj-were-there no such'valves.-

that I amenabled toflutiliz'e the air-pressure 'expansivelyf For'instahce, I arrange that, [thecubic capacit -of the cylinder of the piston hammer 'shal be greater than the .vol-

umeof air di's'plac'ed by each; stroke of 'the, compressor whenfth e predetermined pres: '6 sure is attained-in the tubes; so that when only of "its stroke the air to-fthetool is cut ofl",

' (normal-pressureat'w 'ch the'valve closes, Y therest ofjthe stroke eing completed withavery' highspeed the time l'ostin raising the .extent. The air under each impulse may thus 1 pressure within-thetubes. at the predeter-' 'mined level or-a little below, so that when spindles with a small bore-9F, which will permlt air from; the compressor to'pa'ss trom' the' ports .-6' into "the chamber 10 behind the valve-stem, as illustrated in thedetail view;

hold u the air within the conveying-tubes until t e predeterminedpressureis exceeded,

ble'tubes but as the. compressor is worked at requisite pressure is inappreciable. Whenit s desired to tempora'rilysuspend the working of the tool, it may be restarted more-promptly the outlet 8 by .means of the valve!) instead of opening it to its full Ipressure attained at e allowed to escape through the outlet 8,while maintaining the:

the valve 9 is closed the starting of the tool-"is practically instantaneousq t Y In order to obviate the u'seof very strong, springs to maintain the valves34 closed uncompress when the v valves are to be openedto pass air, I may form the valves andtheir Fig; 8. .i The pressure thus obtained upon the in holdingfthe valve on its seat, "and the spring may be correspondingly weakened, so

The capacity of the compressor-cylinders air on every stroke of the piston to displace. the spring-loaded valves 3'fand4 to drive the piston-hammer at back and forth with the re-' the number of blows per minute of the tool is determined by the number of revolutions made by the crank of the compressor. As I the spring-loaded valves in the toolandthe back-pressure. valves in the air-compressor,

it isnot'possible.jfor -the pi'ston haIn-mer to the piston of the compressor as would hap One of the advantages of m'y" vention'is'.

thepiston-hamme'r-has traversed a portion being i dueed intheponducting-pipeto. the

admitted to exsand; and t piston" I-can thus reduce ows per minute to decrease piston harhmer with a high-velocity stroke en thand as small- '-the ertcess of'such pressure at each-stroke of the alracompressor to drive the piston-hamout further admission'bf'air allowing'the air hus increase the velocityof the the number of b vibration andi obtain a I may, ifdesired, use equal air pressuresfor the-blow and return stroke; the {useof -h1 h-pressure air is notso economicalan'dfis' B55716, to set up obj'ectibnablejreeoil, I

I- prefer that T the tubes conducting- .the ressure' to the tool shall befas short in diameter as possible,

so t at the tool. will start work Iiromptly. .-o'i1f stood, further,that the designof thetooljhnd; the details of construction may be varied to somejextent-so-longas the gistlof my-inven-s tion ispreserv'ed; 7 1 i The =-invent1on ay ..also She, adapted to larger- 'percussive toolsy'such' as IOCkf rills l de'clare that whatil claim-,isg t the valve 9 being closed. It must be-under "1. In power-hammersand like percussive I -.tools worked in conjunction with an air-come pressor, a piston-hammerin the tool two tubes .for conducting' .;th'e air pressureto the tool means for retaining the airspressure gener ated'at each stroke of the compressor-. within' the tubes until -.a predetelfniined pressure is obtained in the tubesand-means for utilizing mer of the tool'foack and forthsubstantially as described. it

2. "In power-hammers and like percussive tools, the combination of a 'se arate air-com press'orto each-tool; two tu esconn'ecting the compressor to each tool,-back-pressure valves in the compressor and loaded valves inthe-"t'ool for holdingup the airpressure ;gen T cratedat each stroke of the compressor until. a predetermined pressureis attained the two tubes and means for conducting theyexeg cess of. such pressure on each-strokeof the'gair-i compressor to the piston-hammer of the tool-- substantially as described-i I 3. ApoWere-hammer comprisin a reciprocatm'g piston-'hammert erem,sa1

' cylinder having inlet and'exhaujst ports therein; spring-loaded valves governing :said ports and a pistonwalveactuated'bythe-a r to ad exh usts v 4; Ajpowephammer consisting, of cyli lij a'ylinder' l. 5 under pressure to alternately 0 .en one-port;

'tairunderpressure an the other to admit air under pressure and the other to ex- In testimony whereof I have signed my haust and means for conducting the exhaust name to this specification. in the presence of to atmosphere from the port not under prestwo subsoribin witnesses.

I sure, said Cylinder also having an exhaust- HARitY BENVVELL STOCKS. 5 port and a valve actuated by the operator Witnesses:

tojgovern said exhaust-port to start and stay JOSHUA ENTWISLE,

the tool, substantially as described. ALFRED \YATES. 

